How robust is the V6 to V4 infrastructure?

["Naslund, Steve" <SNaslund () medline com>]

A question came to mind with all the discussion of ipv6 vulnerabilities.  I am wondering for those with a lot of real 
world pure IPv6 connectivity, how robust have been the V6 to V4 gateways necessary for intercommunication between 
native IPv6 hosts and the IPv4 world?  I was thinking that going to native ipv6 depends heavily on these gateways being 
reachable and having fairly high performance characteristics.  How are the service providers doing providing these 
services?

Steven Naslund
Chicago IL